Process-scale applications for the purification of monoclonal antibodies (MAbs) or virus filtration typically utilize bind-and-elute processes, and flow-through processes, such as anion exchange (AEX) and hydrophobic interaction (HIC) chromatography processes, to remove host cell proteins (HCP) and other impurities from a liquid sample, or feed. Typically, the operating conditions for these flow-through processes are chosen such that the target proteins (e.g., MAbs) are not retained on the chromatography surface and, as a result, flow through the chromatography device. Typically, the operating conditions for bind-and-elute processes are chosen such that the target proteins (e.g., MAbs) are retained or bound on the chromatography surface and then recovered by an elution step, wherein the bound target protein is displaced from the chromatography surface and recovered.
For traditional AEX chromatography resins, it is often necessary to dilute the feed prior to loading the chromatography device to reduce solution conductivities to levels that promote the binding of impurities. The inconvenience and time commitment required for such feed dilution has provided the impetus to develop salt-tolerant functionalities that do not require feed dilution for efficient adsorption of impurities. While the capacities for traditional AEX membranes are typically in the range of about 100-200 g MAb/mL resin, corresponding capacities for salt-tolerant membrane adsorbers are greater and range, for example, from about 4-7 kg MAb/L resin. However, for a chromatography process to be economical at a process scale, the capacity of the chromatography resin should preferably be about 10-15 kg MAb/L membrane or greater.
Thus, there is a current need to develop methods for increasing the capacity of existing chromatography resins and devices to levels that would render flow-through processes, bind-and-elute processes, and simulated flow-through processes more economical at a process scale.